Improvement in wood-sokews



@uiten faire identici @Hita HARVEY HARwooD, 'or UTICA, Naw YoRK. Letters Pam# No. 65,666, dated June 11, 1867.

IMPROVEMENT IN WOOD-SOREWS.

@la flgmul riferita tu in'tlgese tetttrs 33mm mit mating gmt nf tige 5mm.

TO ALL WHOM IT MAY CONGERN:

Be it knownthat I, HARVEY' J. IIARWOOD, of Utica, in the county of Oneida, aindnState of New York, have invented a newl and useful Improvement in VVood-Screws `andI do hereby declare that the following is a full, clear, and exact description of the construction and operation thereof, reference being hadto the annexed drawings, making a part of this specification, in which-F` i Figures 1 and 11- are longitudinal elevations of variations of single-threaded screws.

Figures 2 and 12 are end views of single-threaded screws shown in figs. 1 and 11.

Figures 3, 4, and 8 are longitudinal elevations of variations cf double-threaded screws.

Figure 5 is an end view of the double-threaded screw shown in fig. 4.

' Figures 6 and 9 are longitudinal elevations of variations of triple-threaded screws.

Figures 7 and 10 are end views of the triple-threadedscrews shown in figs. 6 and 9.

It will be' seen by referring to the drawings that the lips come to an edge, or nearly to an edge, and are formed so deep that all of the end of the screw is in a`lip, as seen in the single-threaded screws, figs. 1, 2, 11, and 12, orinto lips, as seen in the double and triple-threaded screws, figs.' 3, 4, 5, (i, 7, 8, 9, andIO,

The nature of m'y invention consists in the form of the lip points on metallic screws made to enter wood.

To enable others skilled in theart to make and use my invention, I will proceed to describe its construction and operation. l

The screws can be made of the metal and in theform desired by any of the well-known means now in use. I prefer to thread and point the screws by rolling the blanks between dies made for that purpose. The screws can be operated in the same manner as the gimlet-pointed screw, and those that have more than one thread are operated in proportionally greater rapidity. Heretofore screws have been made with the core and thread both tapering at the point of the screw, or without `either core or thread tapering at the point end of 'the screw, as they were made before the gimlet point was invented, while in mine the core tapers at the point end of theV screw, and terminates a little short of the end of the screw, while the diameters ofthe threads or lips forming the point are not varied much, if any, from the diameter of the rest of the'screw. 'They readily enter wood and hold to the extreme point better than any other screw now in use. The point or lip or lips of these screws `open the wciodsuciently for the rest of the thread on the screw to enter, and there is no farther displacement of the Wood except such as is produced by the core uponthe edge ofthe thread as it follows the point; therefore it is less liable to split the wood than other screws, and forms a better thread in the wood. The cutting or entering edges of these screws do not all assume the same form; some have around or curved entering edge,

figs. 5 and 10; on some the entering or-cutting edge is nearly straight from the centre of the screw out; others have a hook-shaped entering or cutting edge, figs. 1, 2, and 6. The pitchis greater between the lip and the thread than between two contiguous threads. i

What I claim as my invention, and desire to secure by Letters Patent, is- 1. Forming the end of 'the screw in to a lip or lips, substantially as described. 2. Extending the lip or lips of the screw beyondthe terminus-of the'core, ysubstantially as describedv 3. Retaining the full size of the screw at the' point without continuing the core to the point. 4. Increasing the pitch betweenthe lip and first thread, substantially as described. HARVEY J. HARw'ooD.

Witnesses:

J. FRANLIN RE'IGART, i W. F. HELLEN. 

